Sugar Recovery and Fermentability of Hemicellulose Hydrolysates from Steam-Exploded Softwoods Containing Bark
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- 作者：Abdel Boussaid ; Yijin Cai ; Jamie Robinson ; David J. Gregg ; Quang Nguyen ; and John N. Saddler
- 刊名：Biotechnology Progress
- 出版年：2001
- 出版时间：October 2001
- 年：2001
- 卷：17
- 期：5
- 页码：887 - 892
- 全文大小：58K
- 年卷期：v.17,no.5(October 2001)
- ISSN：1520-6033
文摘
The hemicellulose sugar recovery and ethanol production obtained from SO2-catalyzedsteam explosion of a mixed white fir (70%) and ponderosa pine (30%) feedstockcontaining bark (9% dry weight/dry weight) was assessed. More than 90% of theavailable hemicellulose sugars could be recovered in the hydrolysate obtained aftersteam explosion at 195 
C, 2.38 min, and 3.91% SO2, with 59% of the originalhemicellulose sugars detected in a monomeric form. Despite this high sugar recovery,this hydrolysate showed low ethanol yield (64% of theoretical yield) when fermentedwith a spent sulfite liquor-adapted strain of Saccharomyces cerevisiae. In contrast,most hydrolysates prepared at higher steam explosion severity showed comparableor higher ethanol yields. Furthermore, the hydrolysates prepared from bark-freefeedstock showed better fermentability (87% of theoretical yield) despite containinghigher concentration of known inhibitors. The ethanol yield from the hydrolysateprepared from a bark-containing wood sample could be improved to 81% by an extrastage acid hydrolysis (121 C for 1 h in 3% sulfuric acid). This extra stage acidhydrolysis and steam explosion at higher severity conditions seem to improve thefermentability of the hydrolysates by transforming certain inhibitory compoundspresent in the hydrolysates prepared from the bark-containing feedstock and thuslowering their inhibitory effect on the yeast used for the ethanol fermentation.
C, 2.38 min, and 3.91% SO2, with 59% of the originalhemicellulose sugars detected in a monomeric form. Despite this high sugar recovery,this hydrolysate showed low ethanol yield (64% of theoretical yield) when fermentedwith a spent sulfite liquor-adapted strain of Saccharomyces cerevisiae. In contrast,most hydrolysates prepared at higher steam explosion severity showed comparableor higher ethanol yields. Furthermore, the hydrolysates prepared from bark-freefeedstock showed better fermentability (87% of theoretical yield) despite containinghigher concentration of known inhibitors. The ethanol yield from the hydrolysateprepared from a bark-containing wood sample could be improved to 81% by an extrastage acid hydrolysis (121 C for 1 h in 3% sulfuric acid). This extra stage acidhydrolysis and steam explosion at higher severity conditions seem to improve thefermentability of the hydrolysates by transforming certain inhibitory compoundspresent in the hydrolysates prepared from the bark-containing feedstock and thuslowering their inhibitory effect on the yeast used for the ethanol fermentation.